Buoyant signal flare

ABSTRACT

16. A flare device for use with an explosively actuated mine anchor-line cutter, comprising a buoyant flare, and means for attaching the flare to such a cutter, said means being separable from the cutter by the firing of the cutter under water to sever an anchor-line, whereby the flare will be released, the flare including a gas-producing chemical, water-pressure responsive means sealing the chemical away from water as long as the flare is in deep water, and means for moving said water-pressure responsive means out of said sealing position when the flare rises out of said deep water.

[4 1 May 13,1975

United States Patent 1 91 Temple BUOYANT SIGNAL FLARE Inventor: RobertTemple, Swiss/ale, PZL Przniary Examzrzer-Benyamm A. Borchelt AssistantExammer.1ames M. Hanley [73] Assignee: Mine Safety Appliance Company.Attorney, Agent, or Firm-Brown, Murray, Flick &

Pittsburgh, Pa. Peckham Feb. 18, 1957 Appl. No.: 640,754

[22] Filed:

EXEMPLARY CLAIM 16. A flare device for use with an explosively actuatedmine anchor-line cutter. comprising a buoyant flare and means forattaching the flare to such a cutter. said means being separable fromthe cutter by the firing of -30 sm I981 9 v/ QbmQ a s, m h8 3 2 AHA/7 12.1 1 2 unn M4MH F112 1 .10 m 9 WW ""3 em ".59 O m m mm UIF the cutterunder water to sever an anchor-line.

[56] References Cited UNITED STATES PATENTS whereby the flare will bereleased. the flare including a gas-producing chemical, water-pressureresponsive means sealing the chemical away from water as long as theflare is in deep water and means for moving said water-pressureresponsive means out of said sealing position when the flare rises outof said deep wa 7 7939 2129 9 .H/H "9 9 u. u u H n. W W me I m e k fim mwwa fleefe ATVKLM 87 567 345555 999999 HHHHHH 662 25 769445 9070400 6 ,91 92336 24239 22227.2

FOREIGN PATENTS OR APPLICATIONS 16 Claims 5 Drawing Figures PATENTED MAY1 3 1975 SHED 10? 2 BUOYANT SIGNAL FLARE This invention relates to thecutting of the lines by which explosive mines are anchored in bodies ofwater, and more particularly to buoyant signal flares carried by suchtools and released by them when the lines are cut.

In my copending Pat. application, Ser. No. 591 ,368, filed June 14,1956, I have shown and described several different signal flares thatcan be used with mineanchor line cutters of the explosively actuatedtype. When such a cutter encounters a mine-anchor line, the cutter isfired and the line is cut. Simultaneously, the flare is released fromthe cutter and floats to the surface. As it is released from the cutter,a chemical carried by the flare is exposed to the surrounding water. Thewet chemical is one that generates a gas that will burn the moment thechemical reaches the air above the water. The purpose of the flare is toprovide a floating torch that will show that a mine has been cut looseand has risen to the surface nearby. Of course, the flare has itsprincipal utility when mine sweeping is done at night. At such times,there is always the danger of a floating mine, which has been cut loose,being lost or being run into by another ship in the mine sweeping fleet,due to the fact that the darkness hides the mine. Although the flaresshown in my copending application are satisfactory in general, it hasbeen found that when they are released in deep water, an undesirableamount of the gas-generating chemical is consumed before the floatreaches the surface of the water. This shortens the length of time thatthe flare will burn above the water and may also reduce the size of theflame. Also, when the float has to rise from a great depth, it may taketoo long, with the result that it does not reach the surface as soon asdesired. In addition to the distance that the float must travel, thechemical has a longer time in which to become soaked with water, whichmay retard ascent.

It is among the objects of this invention to provide a signal flarewhich will rise to the surface of a body of water very rapidly and whichwill not start to release gas until the flare is near the surface.

In accordance with this invention, a buoyant signal flare is providedwith a tubular passage having an exposed end. Slidably mounted in theexposed end of the passage is a sealing plug that is held therein by thepressure of water against the plug as long as the flare is in deepwater. However, as the flare rises toward the surface of the water, itreaches a point where the water pressure against the plug is overcome bythe pressure in the opposite direction of a spring. The spring thenpushes the plug out of the passage so that water can reach a chemical inthe passage. The chemical is the kind that, when wet, will produce a gasthat will burst into flame when it reaches the air above the water. Itis therefore necessary to keep the chemical dry until the flare is nearthe surface of the water. For best results, the float with which theflare is provided is a hollow sphere.

The invention is illustrated in the accompanying :irawings, in whichFIG. 1 is a fragmentary plan view of the cutting end )f a mine-anchorline cutter provided with my imaroved flare;

FIG. 2 is an enlarged fragmentary front view of the :utter, showing partof it and the flare broken away in ;ection;

FIG. 3 illustrates a released flare floating on a body of water andproducing flames;

FIG. 4 a fragmentary horizontal section through a modified cutter andflare, and;

FIG. 5 shows the flare floating and producing flames.

Referring to FIGS. 1 and 2 of the drawings, a stabilizing fin 1 has itslongitudinal axis extending in the direction in which the cutter ispulled through the water by a sweep line 2 extending backward andlaterally from a mine sweeper (not shown) in a wellknown manner. Thefront edge of the fin is inclined to its longitudinal axis the samedegree as the sweep line. This front edge is provided at its oppositeends with integral ears 3 that hook over the sweep line. Bolts 4,extending through the fin and each ear, hold the fin on the sweep line.

Rigidly mounted on the front portion of the fin is the metal frame 6 ofthe cutting tool. The longitudinal axis of the frame extends across thefin, and the frame is set back from the front corner of the fin so thatonly a small amount of the frame extends across the inclined front edgeof the fin. The front side of this outwardly projecting portion of theframe is provided with a recess 7 that extends lengthwise of the frame.The frame also is provided with a longitudinal bore extending inwardlyfrom the inner end of the recess, and this bore normally contains acutting chisel 8 that is held in retracted position by a shear pin 9extending through it and the surrounding frame.

The end of the frame beside the recess is provided with a slot 11 forreceiving a tongue 12 on one end of a guide member 13. The tongue andframe are provided with aligned transverse passages, through which ashear pin 14 extends. The guide member 13 extends across the end of therecess 7 to form an anvil l5 and then the guide turns and extends alongthe front side of the recess toward the chisel. At a point spaced fromthe chisel, the guide is inclined forward away from the frame to form afinger 16 that will intercept a mineanchor line and direct it into thecutting notch formed by recess 7 between the guide and frame.

When a mine-anchor line 18, across which the sweep line and fin havebeen dragged, is caught in the cutting notch, it is cut by the chiselwhich is driven against it by the force of an explosion from a cartridge(not shown) removably mounted in the frame at the inner or rear end ofthe chisel. During cutting, the mine line is backed up by the front andback walls of the cutting notch, and by the anvil 15 in the path of thechisel. To explode the cartridge, a firing mechanism is mounted in theinner end of the frame. This mechanism forms no part of this inventionand is not shown, but it can be seen in US. Pat. No. 2,422,506. Itincludes a plunger 19 slidably mounted in a guiding slot 20 extendinglengthwise of the back side of the frame. Connected to the rear end ofthe plunger is a rod 21 that is slidably mounted in a bore through ablock 22 rigidly mounted in slot 20 behind the cutting notch. Theplunger is urged toward the inner end of the frame by a coil spring 23encircling the rod and compressed between the plunger and block 22. Theplunger normally is held in retracted position, with the springcompressed, by means of a trip pin 24 of small diameter extendingthrough guide member 13, across the cutting notch, through the frame andinto a transverse opening 25 in the plunger rod.

When a mine-anchor line 18 enters the cutting notch, it engages the trippin 24, the front end of which is held in fixed position by engagementof its head with guide member 13. As the anchor line bends the pintoward anvil 15, the rear end of the pin is pulled out of the plungerrod, thereby releasing the plunger. The released plunger actuates thefiring mechanism, as described in detail in said patent, and thecartridge is detonated. The force of the explosion builds up until it issufficient to cause the cutting chisel to shear off pin 9. The chiselthen shoots forward, and in cutting the anchor line it also shears offthe portion of trip pin 24 in the cutting notch. Shear pin 14, whichconnects guide member 13 to the frame, is strong enough to hold theanvil in place until the chisel has severed the anchor line. The impactof the chisel against the anvil then causes the tongue 12 of guidemember 13 to shear off pin 14 and slide out of frame slot 11. Releaseand loss of the guide member in this manner is justified because,otherwise, the next mine-anchor line might catch in the cutting notch,where it would not be cut.

As soon as a mine-anchor line is cut, the mine that is thereby releasedrises to the surface of the water and floats there until detonated insome suitable manner. It is a feature of this invention that thepresence of the mine floating on the water is clearly indicated at nightwhen the mine otherwise might not be seen. Accordingly, a buoyant flareis carried by the cutter in such a manner that it will be released whenthe cutter is fired and will rise to the surface with the mine, where itwill immediately burst into flame and serve as a beacon.

The flare shown in FIGS. 1, 2 and 3 includes a float that preferably isa hollow spherical shell. The float may be made conveniently from twoflanged hemispherical metal cups welded together. It is provided with acircular opening, from which an integral collar 31 projects radially.Extending across the inside of the float and most of the way through thecollar, is a sleeve 32 having an open outer end and a closed inner end.The inner end may be provided with an integral rivet 33 that extendsthrough a hole in the float and is upset to hold the sleeve tightly inplace. Slidably mounted in the outer end portion of the sleeve is a plug34, inward movement of which is limited preferably by a shoulder 35 thatengages the end of the sleeve. The plug is supposed to seal the end ofthe sleeve, and to make certain that a good seal will be produced, theplug may be provided with a circumferential groove, in which a sealingring 36 is compressed for sealing engagement with the inner surface ofthe sleeve.

Disposed inside of sleeve 32 is the chemical 37 that generates the gaswhich produces the flame of the flare. This chemical is calciumphosphide, which may contain calcium carbide. When such a chemicalbecomes wet, it immediately generates a gas. The calcium phosphide gaswill burst into flame in the presence of oxygen, but the calcium carbidegas must be ignited by the first gas. The calcium carbide is used inorder to provide a bright, steady signal flame, because calciumphosphide gas produces an intermittent flame that is not very bright. Ofcourse, the plug in the end of the sleeve keeps the chemical dry untilit is to be used. Preferably, the chemical is disposed in a tubularreceptacle 38 that may be integral with the inner end of the plug andcoaxial with it. The side wall of the receptacle is perforated forentrance of water and escape of gas. The inner end of the receptacle maybe closed by a stopper 39. If there is any likelihood of the chemicalsifting out through the perforated tube, the chemical can be held in amesh bag (not shown). To prevent plug 34 from leaving the sleeve whenthe flare is not in use, the float collar 31, the sleeve and the plugare all provided with registering openings, through'which a safety pin40 ex- 5 tends.

In order to attach this flare to the cutter, preferably to its anvil 15,the outer side of the anvil is provided with a spherical recess 42 forreceiving part of the spherical float, and with a bore 43 for receivingthe float collar. The anvil is also provided with a slot 44 to receivethe safety pin 40, which should not be removed until after the float hasbeen attached to the cutter. The outer portion of the float is held in ametal cup 45, the open side of which fits against the wall of the anvilrecess. The circular edge of the cup is soldered to the anvil at 46. Theside wall of the cup preferably is provided with slots 47 extendinginward from its edge.

When the cutter is fired, the chisel is driven through a mine-anchorline in the cutting notch and against the anvil with tremendous force.The shock of this impact easily breaks the soldered joint 46 between theflare cup and the anvil, and it also causes the segments of the cupbetween its slots to flare out to completely free it from the flare. Thecup immediately separates from the anvil and thereby releases the flare,which quickly rises to the surface of the water. To guard against anypossibility of the flare not separating from the anvil, a strong coilspring 48 may be compressed between plug 34 and the anvil by mountingthe spring in a bore 49 in the anvil behind the plug.

As the flare rises toward the surface, the plug is maintained in placein the sleeve by the pressure of the surrounding water. However, a fewyards below the surface of the water, where the water pressure isslight, that pressure is overcome by the pressure of a coil spring 51against the inner end of the plug. This spring encircles the tubularreceptacle 38 for the chemical and may have its outer end bent andprojected through a hole in the side of the receptacle. The inner end ofthe spring is secured to the sleeve in any suitable manner, such as bypressure of the last turn of the spring radially outward against thesleeve. This pressure can be produced by expanding the last turn beforethe spring is inserted in the sleeve. As soon as the plug is forced outof the sleeve by the spring, the chemical in the tube is wet by thesurrounding water and starts to generate gas. This gas rises to thesurface and bursts into flame as it strikes the air. The flare floatswith most of tube 38 suspended from it by the spring, as shown in FIG.3.

It will be seen that no matter at what depth the flare is released, itwill not start to generate gas until it is near the surface, whereby thegas is conserved until that time. In the deeper water, the waterpressure against the plug is greater than the pressure of spring 51against its inner end, so the plug cannot come out of the sleeve. Onlywhen the flare reaches relatively shallow water is the plug dischargedand the chemical exposed to the water. By using a float formed from ahollow metal shell, the float is very buoyant and will rise through thewater faster than if the float were cork or a similar material. Theadvantage is that the signal becomes active sooner than heretofore.

In the modified embodiment of the invention disclosed in FIGS. 4 and 5,the hollow float 55 is provided with two diametrically oppositeopenings, and a sleeve 56 extends through it and projects from bothopenings. The sleeve and float are soldered together to seal the float.The cup 57 that receives the outer half of the float is provided with aradial well 58 for receiving the adjoining end of the sleeve. Slidablymounted in each end of the sleeve is a plug 59, encircled by a sealingring 60. The plugs are held in place initially by safety pins 61.Extending toward each other from the two plugs are perforated tubularreceptacles 62 joined to the plugs. These tubes contain thegas-generating chemical 63. Encircling each tube is a coil spring 64that is fastened to the outer end of the tube and secured to the centralpart of the sleeve against an internal shoulder 65.

When the cutter is fired and the flare is released from cup 57 and therecess in the anvil 66, the flare will rise through deep water where theplugs will be held in place by water pressure. As the float approachesrelatively close to the surface, the pressure of the springs in thesleeve will push the plugs out of it. The chemical in the tworeceptacles will then become wet and will start generating gas that willburst into flame as it reaches the surface, as shown in FIG. 5. Anadvantage of this particular form of float is that if, for any reason,one plug would stick in the sleeve, it is a practical certainty that theother plug would be pushed out and therefore the flare would operateanyway.

When the floats disclosed herein are made of metal, they should benonmagnetic, such as aluminum. It is highly desirable that the float belight enough to cause the flare to rise through the water at a speed atleast as great as 5 feet per second. Generally, mine sweeping is done ata depth of about 50 feet and at that depth and up to about feet or lessfrom the surface, the springs in the released floats should not bestrong enough to push the plugs out of the sleeves against the waterpressure holding them in place. Before the floats reach the surface,however, the springs will overcome the water pressure against the plugsand push them out to admit water to the chemical. Of course, the plugswill be held in place at depths greater than 50 feet, and the entireflare is designed to withstand pressures at depths at least as great as100 feet.

According to the provisions of the patent statutes, I have explained theprinciple of my invention and have illustrated and described what I nowconsider to represent its best embodiment. However, I desire to have itunderstood that, within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically illustrated anddescribed.

I claim:

1. A buoyant signal flare provided with a tubular passage having anexposed end, the flare including a sealing plug slidably mounted in saidend of the passage and held therein by the pressure of water against theplug when the flare is in deep water, a spring in said passage forpushing the plug out of it when the flare rises from deep water, and achemical in said passage that will produce a self-igniting gas when wetby water after the plug has been pushed out of the passage.

2. A flare according to claim 1, in which said chemical is disposed in areceptacle connected to the inner end of said plug, and the receptacleis provided with an opening for entrance of water when said passage isopened.

3. A flare according to claim 2, in which said receptacle is tubular andin axial alignment with said plug, and said spring is coiled around thereceptacle and permanently connects it with the rest of the flare.

4. A flare according to claim 1, including a float containing saidpassage and chemical and spring.

5. A flare according to claim 4,'in which said passage is formed by asleeve mounted in the float.

6. A flare according to claim 1, including a hollow float and a sleevemounted in the float and projecting therefrom, said sleeve forming saidpassage and containing said plug and spring and chemical.

7. A buoyant signal flare provided with a tubular passage having exposedends, the flare including sealing plugs slidably mounted in the ends ofthe passage and held therein by the pressure of water against them whenthe flare is in deep water, resilient means in said passage for pushingthe plugs out of it when the flare rises from deep water, and a chemicalin said passage that will produce a self-igniting gas when wet by waterafter the plugs have been pushed out of the passage.

8. A flare according to claim 7, including a float and a sleeveextending through it to form said passage.

9. A flare according to claim 8, including a hollow spherical floatprovided with a pair of diametrically opposite openings, and a sleeveextending throughthc float and projecting from said openings and sealedtherein, said sleeve forming said passage and containing said plugs andresilient means and chemical.

10. A signal flare device for use with an explosively actuated anchorline cutter, comprising a buoyant flare provided with a tubular passagehaving an exposed end, means for attaching the flare to such a cutter,said means being separable from the cutter by the firing of the cutterunder water to sever an anchor line, whereby the flare will be released,a sealing plug slidably mounted in said end of said passage andretainable therein by the pressure of water against the plug as long asthe released flare is in deep water, a spring in said passage forpushing the plug out of it when the released flare rises from deepwater, and a chemical in said passage that will produce a self-ignitinggas when wet by water after the plug has been pushed out of the passage.

11. A signal flare device according to claim 10, including a coil springcompressible between said flare and cutter for pushing the flare awayfrom the cutter when said attaching means is separated from the cutter.

12. A mine anchor line cutter assembly comprising an explosively drivenchisel, an anvil in front of the chisel, the side of the anvil oppositeto the chisel being provided with a recess, a concave flare holderfitting against said side and forming therewith a chamber, meansconnecting the holder to the anvil, a float in said chamber, a sleevemounted in the float and projecting therefrom into said recess, asealing plug slidably mounted in the projecting end of the sleeve andheld therein by the inner wall of said recess, said connecting meansbeing separable from the anvil to release the float when the chisel isdriven against the anvil in cut ting an anchor line in deep water, saidplug carried by the released float having an outer end exposed to waterpressure, a spring in said sleeve for pushing the plug out of it whenthe float rises from said deep water far enough for the pressure of thespring to overcome the water pressure against the plug, and a chemicalin said sleeve that will produce a self-igniting gas when wet by waterafter the plug has been pushed out of the sleeve.

13. A buoyant signal flare comprising a receptacle, a chemical in thereceptacle that will produce a selfigniting gas when wet by water,water-pressure responsive means sealing said receptacle while the flareis in deep water, and means for moving said sealing means when the flareis in shallow water to open said receptacle.

14'. A buoyant signal flare comprising a receptacle, a chemical in thereceptacle that will produce a selfigniting gas when wet by water,water-pressure responsive means sealing said receptacle while the flareis in deep water, and a spring operatively connected with said sealingmeans to retract said means when the flare is in shallow water, wherebyto open said receptacle.

15. A buoyant signal flare provided with a passage having an exposedend, the flare including a sealing member held in sealing relation withsaid end of the passage by the pressure of water against said memberwhen the flare is in deep water, a spring for removing the sealingmember from said sealing relation when the flare rises from deep water,and a chemical in said passage productive ofa self-igniting gas when wetby water after said passage has been opened.

16. A flare device for use with an explosively actuated mine anchor-linecutter, comprising a buoyant flare, and means for attaching the flare tosuch a cutter, said means being separable from the cutter by the firingof the cutter under water to sever an anchor-line, whereby the flarewill be released, the flare including a gas-producing chemical,water-pressure responsive means sealing the chemical away from water aslong as the flare is in deep water, and means for moving saidwater-pressure responsive means out of said sealing position when theflare rises out of said deep water.

* l l l

1. A buoyant signal flare provided with a tubular passage having anexposed end, the flare including a sealing plug slidably mounted in saidend of the passage and held therein by the pressure of water against theplug when the flare is in deep water, a spring in said passage forpushing the plug out of it when the flare rises from deep water, and achemical in said passage that will produce a self-igniting gas when wetby water after the plug has been pushed out of the passage.
 2. A flareaccording to claim 1, in which said chemical is disposed in a receptacleconnected to the inner end of said plug, and the receptacle is providedwith an opening for entrance of water when said passage is opened.
 3. Aflare according to claim 2, in which said receptacle is tubular and inaxial alignment with said plug, and said spring is coiled around thereceptacle and permanently connects it with the rest of the flare.
 4. Aflare according to claim 1, including a float containing said passageand chemical and spring.
 5. A flare according to claim 4, in which saidpassage is formed by a sleeve mounted in the float.
 6. A flare accordingto claim 1, including a hollow float and a sleeve mounted in the floatand projecting therefrom, said sleeve forming said passage andcontaining said plug and spring and chemical.
 7. A buoyant signal flareprovided with a tubular passage having exposed ends, the flare includingsealing plugs slidably mounted in the ends of the passage and heldtherein by the pressure of water against them when the flare is in deepwater, resilient means in said passage for pushing the plugs out of itwhen the flare rises from deep water, and a chemical in said passagethat will produce a self-igniting gas when wet by water after the plugshave been pushed out of the passage.
 8. A flare according to claim 7,including a float and a sleeve extending through it to form saidpasSage.
 9. A flare according to claim 8, including a hollow sphericalfloat provided with a pair of diametrically opposite openings, and asleeve extending through the float and projecting from said openings andsealed therein, said sleeve forming said passage and containing saidplugs and resilient means and chemical.
 10. A signal flare device foruse with an explosively actuated anchor line cutter, comprising abuoyant flare provided with a tubular passage having an exposed end,means for attaching the flare to such a cutter, said means beingseparable from the cutter by the firing of the cutter under water tosever an anchor line, whereby the flare will be released, a sealing plugslidably mounted in said end of said passage and retainable therein bythe pressure of water against the plug as long as the released flare isin deep water, a spring in said passage for pushing the plug out of itwhen the released flare rises from deep water, and a chemical in saidpassage that will produce a self-igniting gas when wet by water afterthe plug has been pushed out of the passage.
 11. A signal flare deviceaccording to claim 10, including a coil spring compressible between saidflare and cutter for pushing the flare away from the cutter when saidattaching means is separated from the cutter.
 12. A mine anchor linecutter assembly comprising an explosively driven chisel, an anvil infront of the chisel, the side of the anvil opposite to the chisel beingprovided with a recess, a concave flare holder fitting against said sideand forming therewith a chamber, means connecting the holder to theanvil, a float in said chamber, a sleeve mounted in the float andprojecting therefrom into said recess, a sealing plug slidably mountedin the projecting end of the sleeve and held therein by the inner wallof said recess, said connecting means being separable from the anvil torelease the float when the chisel is driven against the anvil in cuttingan anchor line in deep water, said plug carried by the released floathaving an outer end exposed to water pressure, a spring in said sleevefor pushing the plug out of it when the float rises from said deep waterfar enough for the pressure of the spring to overcome the water pressureagainst the plug, and a chemical in said sleeve that will produce aself-igniting gas when wet by water after the plug has been pushed outof the sleeve.
 13. A buoyant signal flare comprising a receptacle, achemical in the receptacle that will produce a self-igniting gas whenwet by water, water-pressure responsive means sealing said receptaclewhile the flare is in deep water, and means for moving said sealingmeans when the flare is in shallow water to open said receptacle.
 14. Abuoyant signal flare comprising a receptacle, a chemical in thereceptacle that will produce a self-igniting gas when wet by water,water-pressure responsive means sealing said receptacle while the flareis in deep water, and a spring operatively connected with said sealingmeans to retract said means when the flare is in shallow water, wherebyto open said receptacle.
 15. A buoyant signal flare provided with apassage having an exposed end, the flare including a sealing member heldin sealing relation with said end of the passage by the pressure ofwater against said member when the flare is in deep water, a spring forremoving the sealing member from said sealing relation when the flarerises from deep water, and a chemical in said passage productive of aself-igniting gas when wet by water after said passage has been opened.16. A flare device for use with an explosively actuated mine anchor-linecutter, comprising a buoyant flare, and means for attaching the flare tosuch a cutter, said means being separable from the cutter by the firingof the cutter under water to sever an anchor-line, whereby the flarewill be released, the flare including a gas-producing chemical,water-pressure responsive means sealing the chemical away from water aslong as the flare is in deep water, anD means for moving saidwater-pressure responsive means out of said sealing position when theflare rises out of said deep water.